1. Field of the Invention
The present invention relates to a yarn winding apparatus. More particularly, the present invention relates to an apparatus for monitoring abnormality in a yarn winding apparatus.
The apparatus for monitoring abnormality according to the present invention is especially suitable for a yarn winding apparatus for winding at a high speed a spun thermoplastic synthetic yarn, such as, polyester or polyamide.
2. Description of Prior Art
When a yarn is wound onto a bobbin by means of a yarn winding apparatus, there may occur deformation of ribboning, inward movement or uneveness in the wound yarn quality. In the deformation of ribboning, ribboning formed when the wind ratio nears a certain integer is deformed by the pressing of the contact roller. In the inward movement of wound yarn, the wound yarn moves toward the longitudinal center of a package due to variations of pressing force between the contact roller and the bobbin or the yarn layer formed on the bobbin. The uneveness in the wound yarn quality occurs due to variations of the tension in the wound yarn.
In the meantime, in order to meet with the speeding up of the winding speed at 3,000 m/min or more, application of a spindle drive type yarn winding apparatus has been spreading. In a spindle drive type yarn winding apparatus, the control system may easily cause hunting even if the condition of a package surface is only slightly changed. As a result, defects may occur in the winding operation.
If such variations of pressing force or tension in the wound yarn, which cause the inward movement or uneveness of the wound yarn quality, are large, the wound yarn is broken. Accordingly, in this case, winding operation by the winding apparatus cannot be continued. Consequently, the winding operation is necessarily stopped.
Contrary to this, when the variations of pressing force or tension in the wound yarn are not large enough to break the wound yarn, the winding operation is continued. In this case although the yarn was not broken, since the yarn wound on the package has been subjected to the uneven tension as described above, the obtained yarn package may be defective. The defective yarn package may include a portion temporarily subjected to deformation of ribboning or inward movement due to excess variations of pressing force. The defective yarn package may also include a portion temporarily subjected to hunting. Thus, the quality of the wound yarn in the defective package may be uneven due to large variations of the tension in the wound yarn.
Since such a defective package is difficult to be detected by visual inspection of its appearance, it happens to be transferred to the subsequent process for a rewinding or weaving operation. In the subsequent process, there may occur a problem that the yarn cannot be smoothly withdrawn from the wound package due to portions having the deformation of ribboning or inward movement in the package. Alternatively, there may occur a problem of uneven dyability due to the portion subjected to hunting or the uneven quality in the wound yarn.
In the recent years, manufacture of yarn packages having a good unwinding ability and a good yarn quality is desired as the winding speed is enhanced and as the rate of automation in the subsequent process is increased. In order to satisfy the above described requirements, quality control in the yarn winding process becomes of importance.
At the same time, also in the yarn manufacturing process, the yarn processing speed is increasing and human labor has been minimized to decrease the manufacturing cost and to save human labor. In facilitating the speeding up or automation, it is indispensable to eliminate the problems of withdrawal or the problem of uneven dyability. The problems of withdrawal are caused by the deformation of ribboning or inward movement caused by the variations of pressing force or tension in the wound yarn, and the problem of uneven dyability is caused by the uneven quality.
In order to attending at the speeding up or to the minimization of human labor, automation of quality control and automatic selection of defective package in the yarn manufacturing process are becoming indispensable. Further, in order to meet with the speeding up of the winding speed, application of a spindle drive type yarn winding apparatus is increasing. The above-described deformation of ribboning or inward movement may easily occur in such a spindle drive type yarn winding apparatus, if the condition of a package surface is only slightly changed.